Damping device and method for setting natural frequency of damping body in the damping device

ABSTRACT

Installed on a top of a structure ( 1 ) is a base stand ( 11 ) against which damping body ( 3 ) movably rests via a linear guide mechanism ( 12 ). Mounted between the damping body ( 3 ) and the structure ( 1 ) or between the damping body ( 3 ) and a top of a support housing ( 14 ) erected on the structure ( 1 ) is a characteristic-frequency adjusting spring or springs ( 13 ) with an initial tension being applied vertically. Movement of the damping body ( 3 ) causes the spring or springs ( 13 ) to be obliquely and longitudinally expanded to apply horizontal component to the damping body ( 3 ) upon restoring.

TECHNICAL FIELD

The present invention relates to a damping device installed on a top ofa structure such as a towery portion of a suspension bridge, askyscraper, a tower or a pylon to suppress and early attenuatevibrations or oscillation of the structure due to wind load orearthquake, and further relates to a method for setting a characteristicfrequency of a damping body in said damping device.

BACKGROUND ART

In a conventional damping device of this kind, as schematically andexemplarily shown in FIG. 1, guide rails 2 are mounted on a top surfaceof a structure 1 in parallel with a direction of oscillation of thestructure 1, and a damping body or weight 3 rests against the rails 2via wheels 4 horizontally movably along the rails 2. Interposed betweenan end face of the damping body 3 and a support frame 5 erected on thestructure 1 on its one side in the direction of motion of the dampingbody 3 are an attenuator or damper 6 for attenuation of kinetic energyof the damping body 3 and a spring 7 for adjusting a characteristicfrequency of the damping body 3. When oscillation of the structure 1occurs, its oscillation energy is transmitted to the damping body 3 sothat the damping body 3 is reciprocated on the guide rails 2 withdelayed phase of 90° to the oscillation of the structure 1. Then, thekinetic energy of the damping body 3 is attenuated by the attenuator 6to suppress the oscillation of the structure 1.

However, such damping device has a problem that mass, movement strokeand/or the like of the damping body 3 must be selected to afford anoptimum damping effect to the structure 1 and a characteristic frequencyof the damping body 3 must be matched with that of the structure 1,which adjustments are much difficult to perform.

More specifically, in the above-mentioned damping device, thecharacteristic frequency ?₀ of the damping body 3 is given by theequation?₀=(k/m)^(1/2)and attenuation coefficient μ is given by the equationμ=c/{2(mk)^(1/2)}where m is mass of the damping body 3, k is spring constant of thecharacteristic-frequency adjusting spring 7 and c is an attenuating orcontrolling force of the attenuator 6 for attenuating the oscillation ofthe damping body 3. When the characteristic frequency ?₀ of the dampingbody 3 is to be changed, the spring constant of the spring 7 may bechanged from k to k₁ to attain change of the characteristic frequencyinto ?₀′=(k₁/m)^(1/2). Such change of k into k₁ may be performed bychanging the force of the spring 7, which in turn may require adjustmentof spring displacement. However, the change of the spring constant fromk into k₁ is accompanied with change of expansion/contraction stroke ofthe spring 7, which in turn constrains the motion of the damping body 3,leading to the lowered damping effect. Thus, in particular, thestructure 1 with a lower characteristic frequency tends to havemechanical restrictions on the spring 7. For example, when theexpansion/contraction stroke of the spring 7 is to be set to 100 mm,generally the spring 7 is required to have length five times as muchinto 500 mm, leading to a problem of increased two-dimensional spacerequired for installation of the device as a whole.

As a damping device capable of setting a characteristic frequency of adamping body with no mechanical restrictions on spring, there has beenproposed, for example, a damping device as schematically shown in FIG. 2in which a damping body 8 with an arched bottom having radius ofcurvature R rests against two support rollers 9 arranged in a mutuallyspaced-apart relationship on a structure 1 so as to allow freeoscillation into simple harmonic oscillation, or a damping device asschematically shown in FIG. 3 in which a damping body 10 with a V-shapedbottom of angle ? as damping mass equivalently analogous to simplependulum rests against two support rollers 9 on a structure 1 so as toallow free oscillation.

However, these simple-harmonic oscillation type damping devices have aproblem that characteristic frequency is hard to adjust after the radiusof curvature R of the damping body 8 or the angle ? of the damping body10 is once decided.

Moreover, as mentioned above, when the characteristic frequency ?₀ ofthe damping body 3 is to be changed, such change may be obtained into?₀′=(k₁/m)^(1/2) by changing the spring constant of the spring 7 from kto k₁. In this respect, since the actual characteristic frequency of thestructure 1 is not necessarily as designed, a plurality of springs 7with different spring constants are needed to be prepared so as tochoose one of the springs 7 which has the characteristic frequencycorresponding to that of the structure 1; and whenever thecharacteristic frequency of the damping body 3 is required to beadjusted in response to change in characteristic frequency of thestructure 1, the spring 7 must be replaced by that with a correspondingspring constant.

As a damping device capable of both setting and adjusting thecharacteristic frequency of a damping body irrespective of a springconstant of a spring, there has been proposed a damping device asschematically shown in FIG. 4 in which a damping body 10 with a V-shapedbottom as equivalently analogous to simple pendulum rests via linerplates 10 a against two support rollers 9 which in turn are arranged ina mutually spaced-apart relationship on a structure 1 so as to allowfree oscillation. In this damping device, adjustment of thecharacteristic frequency of the damping body 10 requires replacement ofthe liner plates 10 a with those having different thickness, whichreplacement work is extremely troublesome in that large scale equipmentand tools such as hydraulic jacks, lever blocks and/or chain blocks areneeded at a site.

Thus, a primary object of the invention is to provide a damping devicecomprising a damping body adapted for horizontal reciprocal movement anda spring or springs for adjusting a characteristic frequency of thedamping body and which allows the motion of the damping body not to berestricted even when spring constant and/or expansion/contraction strokeof the spring or springs is changed.

A second object of the invention is, in a damping device comprising adamping body adapted for horizontal reciprocal movement and a spring orsprings for adjusting a characteristic frequency of the damping body, toprovide a method for setting the characteristic frequency of the dampingbody in which the characteristic frequency of the damping body can bereadily set and adjusted.

SUMMARY OF THE INVENTION

In order to attain the above-mentioned primary object, according to theinvention, a damping body horizontally movably rests against a structureand a characteristic-frequency adjusting spring or springs are mountedbetween the damping body and the structure such thatexpansion/contraction force is vertically exerted.

Because of the vertical arrangement of the spring or springs, the oreach spring reciprocates about its support point during horizontalmovement of the damping body. This reduces a required amount ofexpansion of the spring or springs and restricts no motion of thedamping body. As a result, the characteristic frequency of the dampingbody can be readily adjusted by changing the spring constant and/orexpansion/contraction stroke of the spring or springs.

A passive type device may be provided such that a damping bodyhorizontally movably rests against a structure, and an attenuator forattenuating moving force of the damping body and acharacteristic-frequency adjusting spring or springs for exertion ofvertical expansion/contraction force are mounted between the dampingbody and the structure. An active type device may be provided such thata damping body horizontally movably rests against a structure, and anactuator for reciprocation of the damping body and acharacteristic-frequency adjusting spring or springs for exertion ofvertical expansion/contraction force are mounted between the dampingbody and the structure.

Instead of the characteristic-frequency adjusting spring or springs forexertion of vertical expansion/contraction force mounted between thedamping body and the structure, a characteristic-frequency adjustingspring or springs may be mounted between the damping body and astationary member erected on the structure to have a position higherthan that of the damping body, which also contributes to no restrictionto movement of the damping body.

An integral construction may be provided by a plurality of damping unitseach of which is constituted by a damping body horizontally movablyresting against a base stand, an attenuator for attenuation of movingforce of the damping body and a characteristic-frequency adjustingspring or springs for exertion of vertical expansion/contraction force,said attenuator and said spring or springs being mounted between thedamping body and the base stand, the damping units being piled one abovethe other on the structure such that their corresponding damping bodiesmay be moved perpendicular to each other and that the upper damping unitis piled on the lower damping unit on the structure; alternatively, anintegral construction may be provided by a plurality of damping unitseach of which is constituted by a damping body horizontally movablyresting against a base stand, an actuator for reciprocation of thedamping body and a characteristic-frequency adjusting spring or springsfor exertion of vertical expansion/contraction force, said actuator andsaid spring or springs being mounted between the damping body and thebase stand, the damping units being piled one above the other on thestructure such that their corresponding damping bodies may be movedperpendicular to each other and that the upper damping unit is piled onthe lower damping unit on the structure. Such integral construction canattenuate oscillation of the structure even if the structure mayoscillate horizontally in any direction.

Movement of the damping body may be guided by a linear guide mechanismso as to lessen noises during the movement of the damping body.

In order to attain the above-mentioned second object, according to theinvention, a resilient structural body or bodies are mounted between astructure and a damping body resting for horizontal reciprocationagainst the structure such that a vertical tension is exerted, aninitial tension of the resilient structural body or bodies beingadjusted to set the characteristic frequency of the damping body.

The initial tension of the vertically arranged resilient structural bodyor bodies themselves is arbitrarily adjustable. Thus, the characteristicfrequency of the damping body can be readily set.

The or each resilient structural body may comprise a spring and aconnecting rod variably adjustable in length, the initial tension beingadjusted by changing the length of the connecting rod; alternatively,the or each resilient structural body may comprise a spring and aconnecting rod which is connected at its end away from the spring to asupport plate which in turn is lapped over and pivotally connected to abracket secured to the damping body or to the structure, the initialtension being adjusted by varying a position of connection between thesupport plate and the bracket. Thus, the characteristic frequency of thedamping body can be set to an optimum value matched with thecharacteristic frequency of the structure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram showing a conventional damping device;

FIG. 2 is a schematic diagram showing another conventional dampingdevice;

FIG. 3 is a schematic diagram showing a further conventional dampingdevice;

FIG. 4 is a schematic diagram showing a still further conventionaldamping device;

FIG. 5 shows a fundamental construction of a damping device according tothe invention in which FIG. 5 a is a schematic side view and FIG. 5 b isa view looking in the direction of arrows A in FIG. 5 a;

FIG. 6 shows a modification of the fundamental construction of FIGS. 5 aand 5 b in which FIG. 6 a is a schematic side view and FIG. 6 b is aview looking in the direction of arrows B in FIG. 6 a;

FIG. 7 shows an embodiment of a damping device according to theinvention in which FIGS. 7 a and 7 b are side and plan views,respectively;

FIG. 8 shows another embodiment of the damping device according to theinvention in which FIG. 8 a is a side view partly in section and FIG. 8b is a view looking in the direction of arrows C in FIG. 8 a;

FIG. 9 is a schematic diagram showing a modification of the embodimentof the damping device shown in FIGS. 7 and 8;

FIG. 10 is a schematic diagram showing a further embodiment of thedamping device according to the invention;

FIG. 11 is a schematic diagram showing a modification of the embodimentshown in FIG. 10;

FIG. 12 is a schematic side view showing a still further embodiment ofthe damping device according to the invention;

FIG. 13 is a schematic plan view partly in section of FIG. 12;

FIG. 14 is a schematic side view showing a still further embodiment ofthe damping device according to the invention;

FIG. 15 is a schematic plan view partly in section of FIG. 14;

FIG. 16 shows a conventional active-type biaxial damping device in whichFIGS. 16 a and 16 b are schematic side and front views, respectively;

FIG. 17 shows embodiments on other adjustment modes ofcharacteristic-frequency adjusting spring in which FIGS. 17 a and 17 bare schematic views on different structures;

FIG. 18 shows other embodiments of characteristic-frequency adjustingspring in which FIGS. 18 a and 18 b are views using a helicalcompression spring and a coned disc spring, respectively;

FIG. 19 is a schematic view showing an embodiment for setting acharacteristic frequency of a damping body in a damping device accordingto the invention;

FIG. 20 is a schematic view showing an embodiment of a resilientstructural body used in execution of the invention;

FIG. 21 is a diagram showing a relationship between displacement of thedamping body and restoring force on the damping body shown in FIGS. 19and 20;

FIG. 22 is a diagram showing a relationship between deflection of ahelical extension spring and the characteristic frequency of the dampingbody shown in FIGS. 19 and 20;

FIG. 23 is a schematic view showing a further embodiment of theresilient structural body;

FIG. 24 is a schematic view showing a still further embodiment of theresilient structural body;

FIG. 25 is a schematic view showing a still further embodiment of theresilient structural body;

FIG. 26 is a schematic view showing a further embodiment of an initialtension adjustment portion of the resilient structural body; and

FIG. 27 is a schematic diagram showing a modification of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the invention will be described in conjunction with thedrawings.

First, an embodiment of a damping device according to the invention willbe described.

FIGS. 5 a and 5 b show a fundamental construction of the invention.Installed on a top surface of a structure 1 is a base stand 11 againstwhich a damping body or weight 3 horizontally movably rests via a guidemechanism such as a linear guide mechanism 12 along a direction ofoscillation of the structure 1. A characteristic-frequency adjustingspring 13, which is a so-called helical extension spring, is mountedvertically between, for example, a lower center surface of the dampingbody 3 in its neutral position, i.e., at a longitudinally intermediateposition of the guide mechanism and the structure 1 just therebelow suchthat spring constant and/or expansion/contraction stroke of the springcan be adjusted; alternatively, as shown in FIGS. 6 a and 6 b andinstead of arranging the spring 13 between the lower center surface ofthe damping body 3 and the top of the structure 1 of FIGS. 5 a and 5 b,the base stand 11 and the damping body 3 are surrounded by a supporthousing 14 as a stationary member and a spring 13 is vertically mountedbetween, for example, a top center surface of the damping body 3 and anupper beam 14 a of the support housing 14 so as to suspend the dampingbody 3 from above.

FIGS. 7 a and 7 b show an embodiment of the invention based on thefundamental construction shown in FIGS. 5 a and 5 b and directed to apassive type. More specifically, installed on a top surface of astructure 1 is a base stand 11 in the form of a rectangular frame.Arranged on laterally opposite sides of the base stand 11 and along alongitudinal direction or direction of oscillation (direction of arrowX) of the structure 1 are linear guide rails 12 a in parallel with eachother against which a damping body or weight 3 longitudinally movablyrests via linear blocks 12 b. Thus, a liner guide mechanism 12 isprovided by the linear guide rails 12 a and the linear blocks 12 b.Attenuators 16 such as oil dampers are horizontally interposed betweensupport stands 15 fixed to lateral centers of forward and backward endsof the base stand 11 and forward and backward ends in the direction ofmotion of the damping body 3, respectively. Furthermore, mounted betweenopposite lateral sides of the forward and backward ends of the dampingbody 3 and corresponding lateral opposite sides of lower portion of thebase stand 11, respectively, are characteristic-frequency adjustingsprings 13 for adjustment of the characteristic frequency of the dampingbody 3 such that they are vertical at longitudinally neutral positionsof the damping body 3.

Each of the springs 13 is fixed at its upper and lower ends to andsupported by plate-like upper and lower holders 17 and 18, respectively.On each of laterally opposite sides of the forward and backward ends ofthe damping body 3 where upper ends of the springs 13 are mounted, twobrackets 19 are fixed in a laterally spaced-apart relationship. At eachof these four positions on the damping body 3, a rod 20 with an eye 20 aat its tip extends through the paired brackets 19 such that the eye 20 alaterally protrudes from the damping body 3 by a predetermined extent.Extends through the eye 20 a of each of the rods 20 and verticallydisplaceably fixed by nuts 22 is a bolt 21 having at its lower end acrevice 21 a to which the upper holder 17 for the spring 13 is connectedthrough a pin 23. At each of positions on laterally opposite sides ofthe base stand 11 and forwardly and backwardly away from a longitudinalcenter of the base stand 11 by a required extent where the lower ends ofthe springs 13 are mounted, a support beam 24 laterally extends throughthe base stand 11 and protrudes from the lateral side of the base stand11 by a required extent. Mounted to each of the protruding ends of thesupport beams 24 is a bracket 25 which extends longitudinally of thedamping body. Each of the brackets 25 has a tip end to which a linkmember 27 is connected at its lower end through a pin 26. The linkmember 27 has an upper end to which the lower holder 18 for the spring13 is connected at its lower end through a bolt 28.

In FIGS. 7 a and 7 b, reference numeral 29 denotes stoppers arranged onfour corners of the base stand 11 in longitudinally opposed relationshipso as to confine the longitudinal motion of the damping body 3.

Upon installation of the thus constructed damping device on the topsurface of the structure 1, initial expansion/contraction force isimparted to each of the springs 13 to make the characteristic frequencyof the damping body 3 matched with that of the structure 1. In thiscase, the vertical position of the bolt 21 connected to each of thesprings 13 near the upper holders 17 is adjusted by screwing the nuts 22to select the force of the spring 13 to thereby set the spring constantand/or expansion/contraction stroke to desired value.

In the state mentioned above, when oscillation of the structure 1 occursby means of, for example, aerodynamic force, its oscillation energy istransmitted to the damping body 3 and is converted to kinetic energywith which the damping body 3 is horizontally moved, which energy isconsumed by the attenuators 16. By such kind of indirect energyconsumption, the oscillation of the structure 1 is promptly suppressed.In this case, the damping force to the structure 1 is obtained optimumby selecting the mass, the movement stroke and/or the characteristicfrequency of the damping body 3. Since the characteristic-frequencyadjusting springs 13 are vertically mounted between the damping body 3and the base stand 11, horizontal movement of the damping body 3 asshown in two-dot chain lines in FIG. 7 a causes the springs 13 toreciprocate about the pins 26 near the lower holders 18 as shown inone-dot chain lines in accordance with the movement of the damping body3 so that the springs 13 are expanded obliquely forwardly and backwardlyto apply horizontal components to the damping body 3 when they restoreto their original state. Thus, each of the springs 13 has a littleamount of expansion in comparison with the horizontalexpansion/contraction of the springs 7 in the conventional device shownin FIG. 1 and does not restrict the motion of the damping body 3. As aresult, with the characteristic frequency of the damping body 3 beingadjusted by the springs 13 or with the restoring force of the springs 13being adjusted, the damping body 3 can be afforded to have a greatmovement stroke. Thus, even in the case of the structure 1 with a lowercharacteristic frequency, the characteristic frequency of the dampingbody 3 can be readily matched to the same.

In the above, the linear guide mechanisms 12 for guiding the horizontalmovement of the damping body 3 may set minimum the gaps between thelinear guide rails 12 a and the linear blocks 12 b so that no loose isgenerated upon reciprocal movement of the damping body 3, leading tolessening of noises generated. In the embodiment, four springs 13 areused; such use of a plurality of springs 13 advantageously contributesto applicability for a damping body 3 with a larger mass.

FIGS. 8 a and 8 b show a further embodiment of the invention directed toactive type. More specifically, in a structure similar to that shown inFIGS. 7 a and 7 b and instead of the attenuators 16 mounted between thedamping body 3 and the base stand 11, a motor 30 as an actuator and anattenuator 31 in the form of a mechanical damper such as rotary torque,rotary hydraulic or eddy damper are arranged laterally centrally atopposite longitudinal ends of the base stand 11, respectively. A ballscrew 33 is arranged and connected between an output shaft 30 a of themotor 30 and an input shaft 31 a of the attenuator 31 via joints 32. Theball screw 33 is rotatably supported at its opposite ends by bearings 35on laterally extending auxiliary beams 34 of the base stand 11 and isthreaded through a nut 36 fixed to the damping body 3. Thus, the motor30 is driven to rotate the ball screw 33 so that the damping body 3 ismoved in unison with the nut 36.

In this embodiment, in order to reduce the overall height of the device,the damping body 3 is provided by a damping body main 3 a made from leadwith concave section to have a through groove at its top in thedirection of movement and a flat base plate 3 b made of stainless steeland having a bottom to which the damping body main 3 a is mounted. Thenut 36 is mounted centrally on the bottom of the base plate 3 b and isdesigned such that the engaged position of the nut 36 with the ballscrew 33 is a center of gravity of the damping body 3. With the dampingbody 3 being thus constructed, the linear blocks 12 b to be engaged withthe linear guide rails 12 a are mounted to the lower surface of the baseplate 3 b via mount members 37 and the springs 13 are used which areshorter in length than those shown in FIGS. 7 a and 7 b. The remainingconstructions are the same as those shown in FIGS. 7 a and 7 b; the sameparts are designated by the same reference numerals.

In the embodiment of FIGS. 8 a and 8 b, when oscillation of thestructure 1 occurs and is detected by an oscillation detection sensor(not shown), a displacement signal phase-controlled on the basis of adetection signal from the sensor is transmitted from a control unit (notshown) to the motor 30 so that the motor 30 is driven in forward orreverse direction. As a result, in unison with the nut 36 engaged overthe ball screw 33 rotatably driven by the motor 30, the damping body 3is longitudinally reciprocated; the kinetic energy of this damping body3 is consumed by the attenuator 31 so that oscillation of the structure1 can be promptly suppressed. Then, as is the case of FIGS. 7 a and 7 b,the springs 13 are obliquely and longitudinally expanded and applyhorizontal components to the damping body 3 upon restoring so that thedamping body 3 can be stably reciprocated in tune with thecharacteristic frequency of the structure 1.

In the above, the restoring force due to the expansion/contraction ofthe spring 13 can be added to the returning force for the damping body 3at its reciprocal movement, so that the drive force of the motor 30 asan actuator can be reduced. Even in case supply of electric power to themotor 30 is stopped due to, for example, power failure and the motor 30fails to make active damping, oscillation of the structure 1 can besuppressed through passive type damping or indirect energy consumptionsuch that, because of the attenuator 31 arranged coaxially of the motor30, the motor 30 is made free to change the energy of oscillationgenerated in the structure 1 into horizontal kinetic energy of thedamping body 3 which is changed through the nut 36 into rotationalenergy for the ball screw 33 which in turn is consumed by the attenuator31. When an eddy damper is used as the attenuator 31, electric currentfor the eddy damper may be adjusted to make variable the dampingcharacteristic of the attenuator 31.

In the above-mentioned embodiments shown in FIGS. 7 a and 7 b and FIGS.8 a and 8 b, in order to make relatively massive damping body 3available, totally four springs 13 are arranged between the laterallyopposite sides of the forward and rearward ends of the damping body 3and the base stand 11. As a modification thereof and as shown in FIG. 9,a support housing 14 just like that shown in FIGS. 6 a and 6 b may beused for suspension from above. Alternatively, as a further embodimentof the invention, between the forward and backward ends of the dampingbody 3 and the structure 1 as shown in FIG. 10 or between the forwardand backward ends of the damping body 3 and the support housing 14 asshown in FIG. 11, each one or more forward and rearward springs 13 maybe arranged slantingly for antagonism (or symmetry) between forward andbackward sides.

FIGS. 12 and 13 show a still further embodiment of the invention whichcomprises two separate damping units 38 a and 38 b each of whichcomprises, just like that shown in FIGS. 7 a and 7 b, a base stand 11 inthe form of rectangular frame, a linear guide mechanism 12 comprising apair of linear guide rails 12 a on laterally opposite sides on the basestand 11 and longitudinally in parallel with each other and linearblocks 12 b each slidably arranged on the linear guide rails 12 a, adamping body 3 longitudinally movably resting via the linear guidemechanism 12 against the base stand 11, characteristic-frequencyadjusting springs 13 for the damping body 3 vertically arranged betweenthe laterally opposite sides of the forward and backward ends of thedamping body 3 and corresponding laterally opposite sides of a lowerportion of the base stand 11, and attenuators 16 for attenuatingrelative oscillation of the damping body 3 to the base stand 11. The twodamping units 38 a and 38 b are vertically piled one above the othersuch that their corresponding damping bodies 3 may have directions ofmovement perpendicular to each other. Interposed between lower surfaceson the four corners of the base stand 11 of the upper damping unit 38 aand upper surfaces on the extensions 40 laterally protruded from thebase stand 11 of the lower damping unit 38 b are leg members 39 each ofwhich has length slightly longer than the height of the lower dampingunit 38 b, the upper damping unit 38 a being integrally arranged on thelower damping unit 38 b.

In the other respects, the parts same as those shown in FIGS. 7 a and 7b are designated by the same reference numerals.

In use of the damping device according to the embodiment shown in FIGS.12 and 13, the damping units 38 a and 38 b are arranged on the structure1 such that the damping bodies 3 of the damping units 38 a and 38 b havedirections of movement in line with directions of two axes (X directionand Y direction perpendicular to the X direction on a plane) along whichthe structure 1 tends to mainly oscillate. FIG. 13 shows a case wherethe damping bodies 3 on the upper and lower damping units 38 a and 38 bare arranged to move in the X and Y directions, respectively.

In the state mentioned above, when oscillation of the structure 1 occursin the X direction due to, for example, aerodynamic force, itsoscillation energy is transmitted to the damping body 3 of the upperdamping unit 38 a and transformed into kinetic energy with which saiddamping body 3 is moved in the X direction. This kinetic energy isconsumed by the attenuators 16 of the upper damping unit 38 a topromptly suppress the oscillation of the structure 1 in the X direction.

On the other hand, when oscillation of the structure occurs in the Ydirection, its oscillation energy is transmitted to the damping body 3of the lower damping unit 38 b and transformed into kinetic energy withwhich said damping body 3 is moved in the Y direction. This kineticenergy is consumed by the attenuators 16 of the lower damping unit 38 bto promptly suppress the oscillation of the structure 1 in the Ydirection.

Further, when oscillation of the structure 1 occurs in mixed X and Ydirection components, the X direction component in its oscillationenergy is converted in the upper damping unit 38 a into the kineticenergy of the damping body 3 by the action just like the above which canbe consumed by the attenuators 16; the Y direction component isconverted in the lower damping unit 38 b into the kinetic energy of thedamping body 3 which can be consumed by the attenuators 16. Thus,oscillation in any direction in the structure 1 can be promptlysuppressed. Thus, even oscillation of a structure 1 with round or squaresection and having no prevailing oscillating directions can besuppressed to ensure living comfortability in the structure 1.

The respective damping units 38 a and 38 b, which have the separatedamping bodies 3, can be independently and arbitrarily set as to massesand/or characteristic frequencies of the damping bodies 3, which factmake it facilitate to respond to cases where parameters such asamplitude and frequency differ with respect to two axle directions atwhich oscillation occurs in each of the structures 1 whose oscillationis to be suppressed.

FIGS. 14 and 15 show a still further embodiment of the invention inwhich a two axle type damping device similar to that shown in FIGS. 12and 13 is made active-type. The damping device of this embodiment haveseparately formed upper and lower damping units 41 a and 41 b.

The upper damping unit 41 a comprises a base stand 11 in the form of arectangular frame, a linear guide mechanism 12 comprising a pair oflinear guide rails 12 a arranged on laterally opposite sides on the basestand 11 and longitudinally in parallel with each other and linearblocks 12 b slidably mounted on the linear guide rails 12 a, a dampingbody 3 longitudinally movably resting via the linear guide mechanism 12against the base stand 11, characteristic-frequency adjusting springs 13for the damping body 3 and vertically mounted between laterally oppositesides of the forward and backward ends of the damping body 3 andcorresponding laterally opposite sides of the base stand 11, a motor 30as an actuator and an attenuator 31 in the form of a mechanical dampersuch as rotary torque, rotary hydraulic or eddy damper which areoppositely arranged on lateral centers on one and the other longitudinalends of the base stand 11, a ball screw 33 connected through joints 32to and between an output shaft 30 a of the motor 30 and an input shaft31 a of the attenuator 31 and a nut 36 fixed to the damping body 3 andthrough which the ball screw 33 is threadedly passed at the center ofgravity of the damping body 3.

The lower damping unit 41 b is substantially the same in structure asthe upper damping unit 41 a except that there is no damping body main 3a of the damping body 3 and only a base plate 3 b is provided. Thus, theupper and lower damping units 41 a and 41 b are arranged one above theother such that the axial ball screws 33 are directed perpendicular toeach other; the leg members 39 are interposed between lower surfaces onthe four corners of the base stand 11 of the upper damping unit 41 a andupper surfaces on the extensions 40 laterally protruded from the basestand 11 of the lower damping unit 41 b. The upper damping unit 41 a isintegrally arranged on the lower damping unit 41 b and serves as adamping body for the lower damping unit 41 b.

In the other respects, the parts same as those shown in FIGS. 8(a) and8(b) are designated by the same reference numerals.

In use of the damping device of FIGS. 14 and 15, just like the dampingdevice in the embodiment shown in FIGS. 12 and 13, the damping units 41a and 41 b are installed on the structure 1 such that the upper dampingunit 41 a and the base plate 3 b of the lower damping unit 41 b havedirections of movement in line with directions of two axes (X directionand Y direction perpendicular to the X direction on a plane) along whichthe structure 1 tends to mainly oscillate. FIG. 15 shows a case wherethe upper damping unit 41 a and the base plate 3 b of the lower dampingunit 41 b are arranged to move in the X and Y directions, respectively.

In the state mentioned above, when oscillation of the structure 1 occursin the X direction due to, for example, aerodynamic force and itsoscillation is sensed by an oscillation detection sensor (not shown), adisplacement signal phase-controlled on the basis of a detection signaltherefrom is transmitted from a control unit (not shown) to the motor 30of the upper damping unit 41 a. As a result, the upper damping unit 41 ais operated like the damping device of the embodiment shown in FIGS.8(a) and 8(b) with respect to the oscillation of the structure 1 in theX direction, so that the oscillation of the structure 1 in the Xdirection can be promptly suppressed.

On the other hand, when oscillation of the structure 1 occurs in the Ydirection and its oscillation is sensed by an oscillation detectionsensor (not shown) just like the above, a displacement signalphase-controlled on the basis of a detection signal from the sensor istransmitted from the control unit (not shown) to the motor 30 of thelower damping unit 41 b. As a result, the upper damping unit 41 a isoperated, as the damping body for the lower damping unit 41 b, just likethe damping device of the embodiment shown in FIGS. 8(a) and 8(b) withrespect to the oscillation in the Y direction of the structure 1, sothat oscillation of the structure 1 in the Y direction can be promptlysuppressed.

Further, when oscillation of the structure 1 occurs in mixed X and Ydirection components, the X direction component in its oscillation canbe, just like the above, promptly suppressed by the upper damping unit41 a; and the Y direction component can be promptly suppressed by theupper damping unit 41 a which also serves as damping body of the lowerdamping unit 41 b. As a result, oscillation in any directions in thestructure 1 can be promptly suppressed. Thus, even oscillation of astructure 1 with round or square section and having no prevailingoscillating directions can be suppressed.

Even when electricity supply to the motors 30 in the above-mentioneddamping units 41 a and 41 b is stopped, the respective damping units 41a and 41 b have attenuators 31 so that, as in the case of the embodimentshown in FIGS. 8(a) and 8(b), passive type damping may be effected.

Since the upper damping unit 41 a has the damping body 3 and can serveas damping body of the lower damping unit 41 b, the respective dampingunits 41 a and 41 b can be independently and arbitrarily set as tomasses and/or characteristic frequencies of the damping body 3 and ofthe upper damping unit 41 a as damping body. As a result, facilitated isresponse to cases where parameters such as amplitude and frequencydiffer with respect to two axle directions at which oscillation occursin each of the structures 1 whose oscillation is to be suppressed.

In a conventional damping device shown in FIGS. 16 a and 16 b, a dampingbody or weight 42 with an arched bottom having a required radius ofcurvature rests against support rollers 43 arranged in mutuallyspaced-apart relationship on a structure 1 so as to allow freeoscillation into simple harmonic oscillation. An arched rack 44 mountedon the damping body 42 along the direction of oscillation is meshed witha pinion 47 on a rotary shaft 46 connected to an output shaft of a motor45. A further damping body or weight 48 with an arched bottom having arequired radius of curvature is supported via support rollers 43 on saiddamping body 42 such that directions of oscillation of the dampingbodies are perpendicular to each other for simple harmonic oscillationat the support rollers 43. An arched rack 44 mounted on the upperdamping body 48 along the direction of oscillation is meshed with apinion 47 on a rotary shaft 46 connected to an output shaft of a motor45 installed on the lower damping body 42. The respective motors 45reciprocally drive the upper and lower damping bodies 42 and 48respectively at required cycles independently from each other forbiaxial damping of the structure 1. Such conventional, active-typebiaxial damping device requires a cable bear (not shown) or the like formobile wiring for supply of electric power to the motor 45 forreciprocation of the upper damping body 48 reciprocated in unison withthe lower damping body 42. However, in the case of FIGS. 12 and 13, suchmobile wiring becomes unnecessary.

Adjustment mode of the spring constant and/or expansion/contractionstroke of the characteristic-frequency adjusting spring 13 may be, forexample, of a type as shown in FIG. 17 a in which a plurality of holes17 a are vertically lined on the upper holder 17 for the spring 13; anda rod 20 fixed to the damping body 3 has a tip end to which, in lieu ofthe eye portion 20 a, a bolt hole 20 b is provided for screwing orinsertion of a bolt 49 or fixing pin thereinto through a selected one ofthe holes 17 a; alternatively, in use of the bolt 49, the holes 17 a asshown in FIG. 17 a may be replaced by a vertical slit 17 b on the upperholder 17 as shown in FIG. 17 b; and any other modes may be applied. Thespring 13 in the above-mentioned embodiments is not restricted to aso-called helical extension spring; for example, as shown in FIGS. 18 aand 18 b, a spring-loaded cylinder structure may be employed which mayaccommodate a helical compression spring 50 or laminated coned discspring 51. Moreover, an attenuator used may be not only of hydraulic ormechanical type but also any type such as electric type or gas type andmay be arranged at any position. Furthermore, in the embodiment shown inFIGS. 8 a and 8 b or shown in FIGS. 14 and 15, the attenuator 31 may beomitted and instead, the motor 30 may be that serving both forattenuation and generation of driving force.

Next, an embodiment for a method for setting a characteristic frequencyof a damping body in a damping device will be described.

FIG. 19 shows an embodiment of the invention in which a base stand 11 inthe form of a rectangular frame is installed on a top surface of thestructure 1. Arranged on laterally opposite sides of forward andbackward ends of the base stand 11 and along a lateral direction ordirection of oscillation (direction of arrow X) of the structure 1 areguide rails 2 in parallel with each other against which a damping bodyor weight 3 laterally movably rests via wheels 4. An attenuator 6 isinterposed between an edge face of the damping body 3 and a supportframe 5 erected on the base stand 11 on a lateral side and centrally inthe longitudinal direction thereof. In such damping device, acharacteristic-frequency adjusting resilient structural body 52 isvertically mounted between, for example, a lower central surface of thedamping body 3 in its neutral position, i.e., at a longitudinallyintermediate position of the guide rails 2 and the structure 1 justtherebelow for vertical tensioning and for prevention of interferencewith the base stand 11 and guide rails 2; an initial tension F of theresilient structural body 52 is adjusted to set the characteristicfrequency of the damping body 3.

The resilient structural body 52 comprises, as shown in FIG. 20 in anenlarged manner, a vertically arranged helical extension spring 56 witha lower end engaged with an upper end of a link member 54 whose lowerend is pivoted for lateral motion via a pin 55 to a bracket 53 securedto the structure 1, and a turnbuckled connecting rod 58 which connectsan upper end of the helical extension spring 56 to a bracket 57 securedto a lower surface of the damping body 3. The turnbuckled connecting rod58 comprises a rod 60 with an upper eye plate 59 and a lower threadedportion 60 a, a rod 62 with a lower eye plate 61 and an upper portion 62a threaded opposite to the threaded portion 60 a and a turnbuckle 63 towhich the threaded portions 60 a and 62 a are screwed. The lower eyeplate 61 of the rod 62 is engaged with the upper end of the helicalextension spring 56 and the upper eye plate 59 of the rod 60 is pivotedfor lateral reciprocation via a pin 64 to the bracket 57 on the lowersurface of the damping body 3. Rotation of the turnbuckle 63 can changethe length of the connecting rod 58, which in turn changes thedeflection of the helical extension spring 56 as tension reaction-force.

When the characteristic frequency of the damping body 3 is to be set tobe matched with the characteristic frequency of the structure 1, theturnbuckle 63 of the connecting rod 58 in the resilient structural body52 is rotated to change the length of the connecting rod 58, whereby theinitial tension F of the resilient structural body 52 as a whole on thebasis of the deflection of the helical extension spring 56 is adjustedto set the characteristic frequency of the damping body 3.

In the state mentioned above, when oscillation of the structure 1 occursdue to, for example, aerodynamic force, its oscillation energy istransmitted to the damping body 3 and is converted into kinetic energywith which the damping body 3 is horizontally moved; the energy isconsumed by the attenuator 6. By such kind of indirect energyconsumption, the oscillation of the structure 1 is promptly suppressed.In this case, the damping force to the structure 1 is obtained optimumby selecting mass, movement stroke and/or characteristic frequency ofthe damping body 3. Since the characteristic-frequency adjustingresilient structural body 52 is vertically mounted between the dampingbody 3 and the structure 1, lateral movement of the damping body 3causes the resilient structural body 52 to expand laterally obliquelyabout the pin 55 at the lower end thereof to apply horizontal componentsto the damping body 3 when it restores to its original state. Thus, thehelical extension spring 56 has a little amount of deflection orexpansion in comparison with the horizontal expansion/contraction of thespring 7 shown in FIG. 1 and does not restrict the motion of the dampingbody 3. Moreover, the initial tension F of the vertical resilientstructural body 52 may be arbitrarily set. As a result, thecharacteristic frequency of the damping body 3 can be readily set to bematched with the characteristic frequency of the structure 1.

The helical extension spring 56 may be used which has a length allowingfor a required variation in length since the tension of the spring doesnot change even if the spring is expanded obliquely from its verticalposition.

In the above, a relationship between the displacement of the dampingbody 3 and the restoring force acting on the damping body 3 is asexemplarily shown in FIG. 21 when, for example, the helical extensionspring 56 has a free length of 600 mm, the spring constant is 755 N/mmand mass of the damping body 3 is 3000 kg. A relationship betweeninitial deflection of the helical extension spring 56 and thecharacteristic frequency of the damping body 3 is as exemplarily shownin FIG. 22. It is known from FIG. 22 that changing the deflection of thehelical extension spring 56 in a range of 30-70 mm can steplessly adjustthe characteristic frequency of the damping body 3 substantially in arange of 0.7-0.9 Hz. Therefore, the characteristic frequency of thedamping body 3 can be set optimum to be matched with the characteristicfrequency of the structure 1; even when the characteristic frequency ofthe damping body 3 is to be re-adjusted in accordance with change incharacteristic frequency of the structure 1, there is no need ofreplacement, in every occasion, into a spring with different springconstant unlike the conventional cases.

FIG. 23 shows a further embodiment of the resilient structural body 52used in the invention in which a piston rod 65 and a helical compressionspring 66 are substituted for the rod 62 and the helical extensionspring 56 shown in FIG. 20. More specifically, the piston rod 65 isprotruded/withdrawn through one of longitudinal end walls of a cylinderbarrel 67 which accommodates a piston 65 b. The helical compressionspring 66 is arranged within the cylinder barrel 67 between saidlongitudinal end wall and said piston 65 b. An upper end of the pistonrod 65 extending from the cylinder barrel 67 is formed with a threadedportion 65 a. In the same manner as shown in FIG. 20, a turnbuckle 63 isarranged between said threaded portion and a lower threaded portion 60 aof a rod 60. Fixed to the other longitudinal or lower end wall of thecylinder barrel 67 is an eye plate 68 which is pivoted for lateralmovement via the pin 55 to the bracket 53 on the structure 1. Theremaining structural features are the same as those shown in FIG. 20;the parts same as those in the figure are designated by the samereference numerals.

Even in use of the resilient structural body 52 shown in FIG. 23, thecharacteristic frequency of the damping body 3 can be readily set andadjusted by adjusting the initial tension of the helical compressionspring 66 based on its contraction reaction force through rotationaloperation of the turnbuckle 63.

FIG. 24 shows a still further embodiment of the resilient structuralbody 52 used in the invention in which a coned disc spring 69 issubstituted for the helical compression spring 66 shown in FIG. 23. Theremaining structural features are the same as those shown in FIG. 23;the parts same as those in the figure are designated by the samereference numerals.

Even in use of the resilient structural body 52 shown in FIG. 24, thecharacteristic frequency of the damping body 3 can be readily set andadjusted by adjusting initial tension of the coned disc spring 69 basedon its contraction reaction force through rotational operation of theturnbuckle 63.

FIG. 25 shows a further embodiment of the resilient structural body 52used in the invention in which installed on the structure 1 in alaterally spaced-apart relationship are supports 70 on and by which inturn a leaf spring 71 is horizontally arranged and carried to be securedto the supports 70. A connecting rod 58 constructed in the same manneras that shown in FIG. 20 is vertically arranged between a center of theleaf spring 71 and a lower surface of a damping body 3. An upper eyeplate 59 of the connecting rod 58 is pivoted via a pin 64 to a bracket57 on the damping body 3. A lower eye plate 61 of the connecting rod 58is pivoted via a pin 55 to a bracket 72 fixed to the leaf spring 71.

In the case of the resilient structural body 52 constructed as shown inFIG. 25, rotation of the turnbuckle 63 changes the length of theconnecting rod 58 so that the leaf spring 71 is elastically deformed andits elastic reaction force is imposed as initial tension. Thus, byadjusting this initial tension, the characteristic frequency of thedamping body 3 can be readily set and adjusted.

FIG. 26 shows a further embodiment of an initial tension adjustmentportion in the form of the resilient structural body 52 in which theconnecting rod 58 shown in FIG. 20 or 25 is modified into a single rodstructure with no turnbuckle 63, the upper eye plate 59 of theconnecting rod 58 being replaced by a support plate 73 with a pluralityof vertically lined holes 73 a. Any one of the holes 73 a of the supportplate 73 is aligned with the hole 57 a of the bracket 57 for connectionby a bolt 74 and nut; by changing this connected position, the initialtension can be adjusted. The structure shown in FIG. 26 may be adoptedas an upper end of the piston rod 65 in place of the rod 60 and theturnbuckle 63 shown in FIGS. 23 and 24. The above-mentioned holes 73 amay be replaced by a slit.

Adjustment of the initial tension of the resilient structure 52 by theadjustment portions as shown in FIG. 26 may also set and adjust thecharacteristic frequency of the damping body 3. The initial tension ofthe resilient structural body 52 may be also adjusted by the portionsshown in FIG. 17 a or 17 b.

The resilient structural body 52 shown in any of the embodiments may bearranged upside down. Moreover, in place of the resilient structuralbody 52 shown in FIG. 19 and arranged between the lower central surfaceof the damping body 3 and the top of the structure 1, a support housing75 as shown in FIG. 27 is arranged as a stationary member to surroundthe base stand 11 and the damping body 3; the resilient structural body52 is vertically mounted between, for example, a top center of thedamping body 3 and an upper beam 75 a of the support housing 75 as ifthe damping body 3 were suspended from above. If allowable in view ofsize of the structure 1 and mass of the damping body 3, rubber may beused as resilient structural body 52. In the embodiments, application toa passive type damping device is shown; however, application to anactive type damping device may be similarly performed.

Industrial Applicability

As mentioned above, a damping device according to the invention has thefollowing excellent effects and advantages.

(1) A damping body horizontally movably rests against a structure and acharacteristic-frequency adjusting spring or springs are mounted betweenthe damping body and the structure such that expansion/contraction forceis vertically exerted. As a result, upon movement of the damping body,the spring or springs are expanded obliquely forwardly and backwardly sothat, even if spring constant and/or expansion/contraction stroke of thespring or springs is changed, no movement of the damping body issubstantially restricted in comparison with cases of the spring orsprings being horizontally mounted; as a result, a characteristicfrequency of the damping body can be readily adjusted with no mechanicalrestrictions on the spring or springs even in a case of the structurehaving a lower characteristic frequency. Moreover, since no spring orsprings stretch out horizontally, the device as a whole can bemanufactured compactly in size and simply in structure.

(2) A passive type damping device may be provided such that a dampingbody horizontally movably rests against a structure; mounted between adamping body and the structure are an attenuator for attenuating movingforce of the damping body and a characteristic-frequency adjustingspring or springs for exertion of vertical expansion/contraction force.

(3) An active type damping device may be provided such that a dampingbody horizontally movably rests against a structure; mounted between adamping body and the structure are an actuator for reciprocation of thedamping body and a characteristic-frequency adjusting spring or springsfor exertion of vertical expansion/contraction force.

(4) Instead of the characteristic-frequency adjusting spring or springsfor exertion of vertical expansion/contraction force mounted between thedamping body and the structure, a characteristic-frequency adjustingspring or springs may be mounted between the damping body and astationary member erected on the structure to have a position higherthan that of the damping body. Such constructions may be also readilyfabricated and does not restrict the movement of the damping body.

(5) An integral construction may be provided by a plurality of dampingunits each of which is constituted by a damping body horizontallymovably resting against a base stand, an attenuator for attenuation ofmoving force of the damping body and a characteristic-frequencyadjusting spring or springs for exertion of verticalexpansion/contraction force, said attenuator and said spring or springsbeing mounted between the damping body and the base stand, the dampingunits being piled one above the other on a structure such that theircorresponding damping bodies may be moved perpendicular to each otherand that the upper damping unit is piled on the lower damping unit onthe structure; alternatively, an integral construction may be providedby a plurality of damping units each of which is constituted by adamping body horizontally movably resting against a base stand, anactuator for reciprocation of the damping body and acharacteristic-frequency adjusting spring or springs for exertion ofvertical expansion/contraction force, said actuator and said spring orsprings being mounted between the damping body and the base stand, thedamping units being piled one above the other on a structure such thattheir corresponding damping bodies may be moved perpendicular to eachother and that the upper damping unit is piled on the lower damping uniton the structure (see FIGS. 14 and 15). By such integral construction,oscillation of the structure can be attenuated even if the structure mayoscillate horizontally in any direction.

(6) Movement of the damping body may be guided by a linear guidemechanism to lessen noises during movement of the damping body.

Moreover, a method for setting a characteristic frequency of a dampingbody in a damping device according to the invention has the followingexcellent effects and advantages.

(1) A resilient structural body or bodies are mounted between astructure and a damping body resting for horizontal reciprocationagainst the structure such that a vertical tension is exerted, aninitial tension of the resilient structural body or bodies beingadjusted to set the characteristic frequency of the damping body. Thus,unlike the conventional cases, the characteristic frequency of thedamping body can be readily set and adjusted with no preparation of anumber of springs for replacement and re-adjustment may be alsoperformed with no hindrance. As a result, the characteristic frequencycan be readily set at site, leading to shortening of construction periodand reducing of construction cost.

(2) The or each resilient structural body may comprise a spring and aconnecting rod variably adjustable in length so that the initial tensionis adjusted by changing the length of the connecting rod; alternatively,the or each resilient structural body may comprise a spring and aconnecting rod which is connected at its end away from the spring to asupport plate which in turn is lapped over and pivotally connected to abracket secured to the damping body or the structure so that the initialtension is adjusted by varying a connected position between the supportplate and the bracket. Thus, the characteristic frequency of the dampingbody can be set to an optimum value matched with the characteristicfrequency of the structure.

1. A damping device comprising: a damping body horizontally movablyresting against a structure; and a characteristic-frequency adjustingspring or springs mounted between said damping body and the structuresuch that expansion/contraction force is vertically exerted.
 2. Adamping device comprising: a damping body horizontally movably restingagainst a structure; an attenuator for attenuating moving force of saiddamping body; and a characteristic-frequency adjusting spring or springsfor exertion of vertical expansion/contraction force, said attenuatorand said spring or springs being mounted between said damping body andsaid structure.
 3. A damping device comprising: a damping bodyhorizontally movably resting against a structure; an actuator forreciprocation of said damping body; and a characteristic-frequencyadjusting spring or springs for exertion of verticalexpansion/contraction force, said actuator and said spring or springsbeing mounted between said damping body and said structure.
 4. A dampingdevice according to claim 1 wherein, instead of thecharacteristic-frequency adjusting spring or springs for exertion ofvertical expansion/contraction force mounted between the damping bodyand the structure, a characteristic-frequency adjusting spring orsprings are mounted between the damping body and a stationary membererected on the structure to have a position higher than that of thedamping body.
 5. A damping device comprising: a plurality of dampingunits constructed integrally, each of the damping units comprising adamping body horizontally movably resting against a base stand; anattenuator for attenuation of moving force of the damping body; and acharacteristic-frequency adjusting spring or springs for exertion ofvertical expansion/contraction force, said attenuator and said spring orsprings being mounted between the damping body and the base stand, thedamping units being piled one above the other on a structure such thatthe corresponding damping bodies thereof may be moved perpendicular toeach other and that the upper damping unit is piled on the lower dampingunit on the structure.
 6. A damping device comprising: a plurality ofdamping units constructed integrally, each of the damping unitscomprising a damping body horizontally movably resting against a basestand; an actuator for reciprocation of the damping body; and acharacteristic-frequency adjusting spring or springs for exertion ofvertical expansion/contraction force, said actuator and said spring orsprings being mounted between the damping body and the base stand, thedamping units being piled one above the other on a structure such thatthe corresponding damping bodies thereof may be moved perpendicular toeach other and that the upper damping unit is piled on the lower dampingunit on the structure.
 7. A damping device according to claim 6 whereinthe upper damping unit is adapted as the damping body for the lowerdamping unit.
 8. A damping device as claimed in claim 1 wherein movementof the damping body is guided by a linear guide mechanism.
 9. A methodfor setting a characteristic frequency of a damping body in a dampingdevice comprising: mounting a resilient structural body or bodiesbetween a structure and a damping body resting for horizontalreciprocation against a structure such that vertical tension is exerted;and adjusting an initial tension of the resilient structural body orbodies to set a characteristic frequency of the damping body.
 10. Amethod for setting a characteristic frequency of a damping body in adamping device according to claim 9 wherein the or each resilientstructural body comprises a spring and a connecting rod variablyadjustable in length, the initial tension being adjusted by changing thelength of said connecting rod.
 11. A method for setting a characteristicfrequency of a damping body in a damping device according to claim 9wherein the or each resilient structural body comprises a spring and aconnecting rod which is connected at an end thereof away from the springto a support plate, said support plate being lapped over and pivotallyconnected to a bracket secured to the damping body or the structure sothat the initial tension is adjusted by varying a connected positionbetween the support plate and the bracket.
 12. A damping deviceaccording to claim 2 wherein, instead of the characteristic-frequencyadjusting spring or springs for exertion of verticalexpansion/contraction force mounted between the damping body and thestructure, a characteristic-frequency adjusting spring or springs aremounted between the damping body and a stationary member erected on thestructure to have a position higher than that of the damping body.
 13. Adamping device according to claim 3 wherein, instead of thecharacteristic-frequency adjusting spring or springs for exertion ofvertical expansion/contraction force mounted between the damping bodyand the structure, a characteristic-frequency adjusting spring orsprings are mounted between the damping body and a stationary membererected on the structure to have a position higher than that of thedamping body.
 14. A damping device as claimed in claim 2 whereinmovement of the damping body is guided by a linear guide mechanism. 15.A damping device as claimed in claim 3 wherein movement of the dampingbody is guided by a linear guide mechanism.
 16. A damping device asclaimed in claim 4 wherein movement of the damping body is guided by alinear guide mechanism.
 17. A damping device as claimed in claim 5wherein movement of the damping body is guided by a linear guidemechanism.
 18. A damping device as claimed in claim 6 wherein movementof the damping body is guided by a linear guide mechanism.
 19. A dampingdevice as claimed in claim 7 wherein movement of the damping body isguided by a linear guide mechanism.
 20. A damping device as claimed inclaim 12 wherein movement of the damping body is guided by a linearguide mechanism.
 21. A damping device as claimed in claim 13 whereinmovement of the damping body is guided by a linear guide mechanism.